Yeah, definetely stuff around with the lighting. I don't have any real experience with renders, but if you add a darker light source, or create a light source, it will enable an ambient render, and add some serious atmosphere.
Also, a sunset in the background, with the sky in a bright array of afternoon sunset colours (reds, oranges etc).
It's sure easier said than done my freind, but keep up the renders and you will only get better.